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Efficient comfortable, home heating management, postulations and the ideal future - long
paulcam
Posts: 54 Forumite
This, as you will soon discover if you care to read is a "pet thing" of mine. I thought I would share a few of my postulations and ask for comment.
My position: I moved from oil fired vented to gas combi sealed system at the start of the month. My house lacks upgraded insulation and currently I only have a 7 day timer and the manual boiler temperature controls. I do have an automated, DIY, smart system in continued development which has led me to these postulations though analysis for the same, but that is not really the point of the post.
Short and hot runs versus always on.
There are a number of factors to consider in this age (of central heating) old question. They are:
Short bursts
I think "most" people use short and hot bursts of heating. Having the heat come on a period of time before they get up or before they get home in the evenings to "heat the house up", then maybe a second heating pulse later in the evening when it tends to get colder. There is usually the option of "Boost" for an hour, "Advance" or just turning the heating on manually when a little extra is needed. The timer is adjusted multiple times through the year to suit the climate.
The pros of this are that the boiler is only running for 2, 4, 6 hours a day saving on electricity used to run it, though not necessarily saving on gas/oil. The downsides are that your temperature will osculate like a "saw tooth" up and down, up and down and assuming you don't use a thermostat (I'll come to them later) it might be too warm for a while and later too cool for a while. It also usually results in "fighting" with the heating, boosting and advancing and manually turning the heating on for colder days risking forgetting to turn it off again. Family wars have started over much less.
For modern combi boilers this can result in a high "loop temp" requirement. ie. the boiler thermostat is set to 70*C or 80*C and even if the radiators are properly balanced the boiler will not be condensing, with a return temp over 54*C and will thus lose 10-15% efficiency.
Always on
Threads on here and elsewhere usually oppose the short burst method with the polar opposite which is "always on". I know that if I set my boiler loop temp to 45*C it will keep the house at a comfortable temperature 24/7 pretty much. That can't be bad can it?
A basic bit of physics stipulates that your house will lose (or gain) an amount heat (in Kilo Joules) per hour. This amount is effectively multiplied by the difference between the indoor and outdoor temperatures. If your house is the same temperature as outdoors, say on a 20*C summer day, then no heat will be gained or lost. However in winter when it's 20*C inside and 2*C outside it will lose heat to the outdoors, easily seen with a thermal camera. The higher the difference, the more heat a given house loses.
So if you are not in the house, the family are all out at work/school, assuming you have set everything up to keep the house a stable temperature then the boiler will be replacing the heat loss 1 for 1. The house at 20*C will lose a lot more heat than the house at, say 15*C, so you are literally buying energy to pump it into the atmosphere while getting almost no benefit from it.
Note: It is incorrect to assume that the short burst method requires you "put the same heat lost back in", simply because the higher the indoor temp the more heat is lost. So always on *will* lose more heat over the day as the house temp is higher for longer.
Proponents of this "always on" approach, will correctly, state that it can keep heat in the fabric of the house, warming the brick work and driving out damp / condensation. Countering the risk with the short hot burst approach allowing the house fabric to cool, condensation to form in the brickwork/windows and potentially causing damp issues.
There are other downsides to this approach to be considered. They can be addressed in various ways, but assuming you have a normal, fairly simple UK heating system such as a gas boiler with a 7 day timer and maybe a thermostat...
1. The boiler requires electricity to run, even when it's not running the gas burner to produce heat. It will typically have pumps, fans and electronics to run and while modern ones are electrically efficient they still consume in the order of 10s or 100s of watts.
2. Either by setting the boiler loop temperature low or by using a thermostat to turn the heating demand on/off the boiler will be "cycling" repeatedly. Cycling adds wear to the boiler and the constant cutting out and then re-igniting wastes fuel. Running the pump 24/7 ages it.
A boiler correctly sized for your house will almost certainly not be able to "modulate" down enough to keep your radiators at 45*C, so it will cycle ON/OFF every 5-10 minutes.
If you have an old house, susceptible to damp, then always on might be your best option. It might pay for itself in a decade or so if you were to modernise the fabric of your building though.
What about a mixture to try and get the best of both worlds?
You might be tempted to put the heating on "low" constantly while you are in the house and rely on the thermostat to turn it off when the house is comfortably warm.
There are gotchas here though. First off, with the heating set to low, after you have been out all day and you come home you will need to run the heating for several hours before you get home to warm it back up. The same heating setting that keeps the house warm but not too warm will not be able to heat it up effectively. Thus, you might need to have the heating on 3 hours before you get home or longer.
What we need is a way to turn the heating on HIGH to warm the house, then back it off to a lower setting as it approaches "comfort temp" and finally switch it off entirely if no heating demand is needed any more. We only use the boiler in-efficiently to warm the house for a short period, then use it for a longer period efficiently, before finally switching it off when it's not needed at all and only switching it on when it's needed. We can leave it off all day when we are out, have it come one before we get home and "do it's thing" until we go to bed.
An even better approach would be to remove the need for the timer entirely and base the heating demand on the presence of people in the house. The system can warm the house a bit during times when it is highly likely someone will be home and then raise it again to a comfortable temperature once a person is actually detected in the house. There are various way to do this today. You can even go as far as detecting which room people are in and bump the temp in that room up a few degrees. 20*C in the living room on Pizza and movie night while the rest is only 18*C, for example.
Systems do exist that will do this. They need to be integrated into your boiler and your boiler has to thus support electronic control. Lots of boiler manufacturers make their own custom thermostats which can turn the boiler up, down or off depending on what the thermostat says. Worcester (and a few related brands) have their EMS protocol system for example. The trouble with these is they are design specifically to lock you into their brand. They viciously defend their equipment, protocols etc. and active try and prevent any old company from making compatible equipment so that they can charge elevated prices for their brand of equipment, choosing occasionally to partner with other companies who agree to keep their prices high too. You'd think this should be illegal, but welcome to the world of software, hardware licensing, patents and price fixing in the 2000s. Stop press, but electronic, wifi thermostats are NOT worth £85!
There are also systems like HoneyWell EvoHome, Nest etc. Quite often you will find they try and lock you into their brand and a component from a HoneyWell system will not work with a component from a nest system for example.
Another downside with these systems is that the data collected and analysed by the systems around who you are, where you live, what you do and your routines are extremely valuable on the global data market and as such most of these companies push "cloud based" system on you and mine your data and probably know more about you than you would hope. That's up to you if you like that or not, but consider what happens when that data falls into the hands of people who aren't meant to have it or it gets used for purposes you didn't expect nor welcome.
Unfortunately, unless you are an electronics wizz, a software engineer and a risk taker you don't have much choice if you want this system. But sure it's only £85 (for a basic integrated thermostat alone), that will pay for itself, won't it? Well, yes.... and no.
Note: You "can" manually intervene to achieve this yourself without electronic control. As my own custom heating controller is off line since I upgraded my boiler and have not, yet, re-integrated it, I am doing it manually. My heating comes on at 4:30pm, I get home at 5:30, the boiler is set to 60*C shortly after the house is up to temp and comfortable. I set the heating down to 45*C and leave it running. Around an hour before I go to bed, the heating shuts off and I raise the temperature to 60*C again for the morning when it only runs for an hour to warm the house for the short period when I get up before I leave for work.
As I hinted to, I am a software engineer and I do electronics as a hobby and will accept this risks of doing this myself over the cost and privacy concerns of a proprietary system. No... I'm not selling it. I'll happily give you any of my software, documentation, design notes, circuit diagrams etc. for free though. The risks remain your own.
Thermostats and TRVs
This brings me to thermostats. In a lot of UK households you will find a single thermostat often placed in the downstairs hallway. You will find thermostatic radiator valves in every room (except the hallway).
This setup is a compromise, it's by no means ideal and neither that single thermostat, nor the TRVs will do a "proper" job, they just do the best they can while making it easy, convenient and most importantly easy to install and cheap. However without spending literally thousands of pounds on a fully smart integrated heating system it's about the best you can get. It's better to have them than to nothing.
So what are the compromises in that system? Well, to be blunt, it's quite simple.
1. Nobody cares what temperature it is in the downstairs hall, there is often only a very loose correlation between the hall temp and other rooms.
2. Nobody cares what temperature it is beside the radiator - there is never a good correlation between the actual room temp and the temp beside the radiator and more advanced electronics ones use complex machine learning to try and deduce the room temp.
... and this is exactly what this system aims to do.
I care what temperature it is on the sofa, I care what temperature it is in the bathroom when I take a shower, I care what temperature it is in the bedroom when I get up in the morning. I hate getting out of bed when the room is freezing, even if it's 20*C in the hallway or the temperature behind the bed where the radiator is in 20*C when the bedroom elsewhere is still 16*C.
So now we are advancing into what the future for efficient, environmentally friendly home heating should bring. I would propose...
1. Insulate your house - loft, walls, doors, windows, floors, while providing good ventilation.
2. Buy a modern heating system, either condensing natural gas (oil if you have to) or go for a heat pump system*. Properly balance your radiators, add radiator reflectors and maybe radiator fans for comfort in certain areas.
3. Place temperature probes in each room you care about the temperature in, place them near where you care what the temperature is, not beside the window or radiator.
4. Install electrically operated radiator valves (similar to underfloor manifold valves)
5. Install a smart demand based control unit that can monitor the temperatures, operate the radiator valves, alter the boiler flow temperature, switch the boiler on/off on timer or by demand.
6. Keep your house comfortable when you care about it being so, let it cool when you don't, but don't let it cool too far. If you let it drop below "dew point" condensation will form. Due point can be any where up to 10*C. So maybe something like, 19-20*C when home in the rooms we care about, 15*C overnight and 10*C as a minimum, even when on holidays.
In rooms you don't care about, fit a TRV as a compromise.
We need to encourage systems that can do this to be made affordable and force open standards upon HVAC equipment and software providers to make this more accessible for UK homes. You should be able to mix and match different brands in a single system to boost competition, flexibility and affordability. The data they collect and what they do with it, needs to be clearly outlined to the consumer and tightly regulated.
* Heat pump systems. Their rally cry is that they produce a kind of "over unity", in that they can provide upwards of 3 or 4 times the amount of heat compared to the electricity they use. The downside is that it takes 3 times as much fossil fuel to produce that electricity than it would yield if you burnt it in your boiler. For every kWh of electric, the power station burns 3 kWh of gas (give or take), so, like electric cars they are not anywhere near as green as they first appear. You can of course offset it with solar panels on the roof which is almost ideal, except of course it won't work on dark days or at night and produces much less in winter when you need more. The same can be said for your electric car. Solar storage systems are expensive, require maintenance, take up space and have environmental impacts and the most important factor everyone seems to forget, they are only practical if you are producing more power than you are consuming during the day.
The other downside that that heat pump systems tend to only produce low level heat, 40-45*C max, which is next to useless for warming a house up, but will provide a good effort at keeping it warm. Thus you might be best backing it up with an occasional use gas boiler or, if you must, electric heater.
On electric space heaters. There is only one use of these that is efficient. If you want to heat a single room to a higher temperature for a short time. It would be more efficient to use a small electric heater for a short time than to run the larger gas/oil boiler to heat a single room. A valid example might be an infrared heater in a bathroom. Although I'm not sure they will pass electrical safety codes these days, maybe they would.
Economy 7 was probably, money aside, the worst, least efficient, most environmentally damaging heating system ever introduced in the UK and probably several times worse than even coal fired heating. It was however great for electricity supplier profits.
Another thing I have seen that needs to be stopped.... people turning the heating on in summer just to dry clothes on the radiators. Don't do this, it's extremely inefficient! It so inefficient you would be better off using the tumble dryer!
One final comment.
Financially efficient != Environmentally friendly. Buying energy when it's cheap does absolutely zero for the environment, the fossil fuel still gets burnt. The only reasons electricity can be cheaper overnight is engineering reasons due to how supply/demand, electrical grid balancing happens and how power plants work. There are even companies who pump water up hill at night when electric is cheaper and use it to generate power on the way down when they can sell it for a higher price during the day. In real net terms this is a environmentally impacting waste. But people make money so it must be good, right? Wrong.
My position: I moved from oil fired vented to gas combi sealed system at the start of the month. My house lacks upgraded insulation and currently I only have a 7 day timer and the manual boiler temperature controls. I do have an automated, DIY, smart system in continued development which has led me to these postulations though analysis for the same, but that is not really the point of the post.
Short and hot runs versus always on.
There are a number of factors to consider in this age (of central heating) old question. They are:
- Heat loss
- Boiler efficiency
- Heating loop temperature
- Comfort
- Thermostats
- How good your timer is
Short bursts
I think "most" people use short and hot bursts of heating. Having the heat come on a period of time before they get up or before they get home in the evenings to "heat the house up", then maybe a second heating pulse later in the evening when it tends to get colder. There is usually the option of "Boost" for an hour, "Advance" or just turning the heating on manually when a little extra is needed. The timer is adjusted multiple times through the year to suit the climate.
The pros of this are that the boiler is only running for 2, 4, 6 hours a day saving on electricity used to run it, though not necessarily saving on gas/oil. The downsides are that your temperature will osculate like a "saw tooth" up and down, up and down and assuming you don't use a thermostat (I'll come to them later) it might be too warm for a while and later too cool for a while. It also usually results in "fighting" with the heating, boosting and advancing and manually turning the heating on for colder days risking forgetting to turn it off again. Family wars have started over much less.
For modern combi boilers this can result in a high "loop temp" requirement. ie. the boiler thermostat is set to 70*C or 80*C and even if the radiators are properly balanced the boiler will not be condensing, with a return temp over 54*C and will thus lose 10-15% efficiency.
Always on
Threads on here and elsewhere usually oppose the short burst method with the polar opposite which is "always on". I know that if I set my boiler loop temp to 45*C it will keep the house at a comfortable temperature 24/7 pretty much. That can't be bad can it?
A basic bit of physics stipulates that your house will lose (or gain) an amount heat (in Kilo Joules) per hour. This amount is effectively multiplied by the difference between the indoor and outdoor temperatures. If your house is the same temperature as outdoors, say on a 20*C summer day, then no heat will be gained or lost. However in winter when it's 20*C inside and 2*C outside it will lose heat to the outdoors, easily seen with a thermal camera. The higher the difference, the more heat a given house loses.
So if you are not in the house, the family are all out at work/school, assuming you have set everything up to keep the house a stable temperature then the boiler will be replacing the heat loss 1 for 1. The house at 20*C will lose a lot more heat than the house at, say 15*C, so you are literally buying energy to pump it into the atmosphere while getting almost no benefit from it.
Note: It is incorrect to assume that the short burst method requires you "put the same heat lost back in", simply because the higher the indoor temp the more heat is lost. So always on *will* lose more heat over the day as the house temp is higher for longer.
Proponents of this "always on" approach, will correctly, state that it can keep heat in the fabric of the house, warming the brick work and driving out damp / condensation. Countering the risk with the short hot burst approach allowing the house fabric to cool, condensation to form in the brickwork/windows and potentially causing damp issues.
There are other downsides to this approach to be considered. They can be addressed in various ways, but assuming you have a normal, fairly simple UK heating system such as a gas boiler with a 7 day timer and maybe a thermostat...
1. The boiler requires electricity to run, even when it's not running the gas burner to produce heat. It will typically have pumps, fans and electronics to run and while modern ones are electrically efficient they still consume in the order of 10s or 100s of watts.
2. Either by setting the boiler loop temperature low or by using a thermostat to turn the heating demand on/off the boiler will be "cycling" repeatedly. Cycling adds wear to the boiler and the constant cutting out and then re-igniting wastes fuel. Running the pump 24/7 ages it.
A boiler correctly sized for your house will almost certainly not be able to "modulate" down enough to keep your radiators at 45*C, so it will cycle ON/OFF every 5-10 minutes.
If you have an old house, susceptible to damp, then always on might be your best option. It might pay for itself in a decade or so if you were to modernise the fabric of your building though.
What about a mixture to try and get the best of both worlds?
You might be tempted to put the heating on "low" constantly while you are in the house and rely on the thermostat to turn it off when the house is comfortably warm.
There are gotchas here though. First off, with the heating set to low, after you have been out all day and you come home you will need to run the heating for several hours before you get home to warm it back up. The same heating setting that keeps the house warm but not too warm will not be able to heat it up effectively. Thus, you might need to have the heating on 3 hours before you get home or longer.
What we need is a way to turn the heating on HIGH to warm the house, then back it off to a lower setting as it approaches "comfort temp" and finally switch it off entirely if no heating demand is needed any more. We only use the boiler in-efficiently to warm the house for a short period, then use it for a longer period efficiently, before finally switching it off when it's not needed at all and only switching it on when it's needed. We can leave it off all day when we are out, have it come one before we get home and "do it's thing" until we go to bed.
An even better approach would be to remove the need for the timer entirely and base the heating demand on the presence of people in the house. The system can warm the house a bit during times when it is highly likely someone will be home and then raise it again to a comfortable temperature once a person is actually detected in the house. There are various way to do this today. You can even go as far as detecting which room people are in and bump the temp in that room up a few degrees. 20*C in the living room on Pizza and movie night while the rest is only 18*C, for example.
Systems do exist that will do this. They need to be integrated into your boiler and your boiler has to thus support electronic control. Lots of boiler manufacturers make their own custom thermostats which can turn the boiler up, down or off depending on what the thermostat says. Worcester (and a few related brands) have their EMS protocol system for example. The trouble with these is they are design specifically to lock you into their brand. They viciously defend their equipment, protocols etc. and active try and prevent any old company from making compatible equipment so that they can charge elevated prices for their brand of equipment, choosing occasionally to partner with other companies who agree to keep their prices high too. You'd think this should be illegal, but welcome to the world of software, hardware licensing, patents and price fixing in the 2000s. Stop press, but electronic, wifi thermostats are NOT worth £85!
There are also systems like HoneyWell EvoHome, Nest etc. Quite often you will find they try and lock you into their brand and a component from a HoneyWell system will not work with a component from a nest system for example.
Another downside with these systems is that the data collected and analysed by the systems around who you are, where you live, what you do and your routines are extremely valuable on the global data market and as such most of these companies push "cloud based" system on you and mine your data and probably know more about you than you would hope. That's up to you if you like that or not, but consider what happens when that data falls into the hands of people who aren't meant to have it or it gets used for purposes you didn't expect nor welcome.
Unfortunately, unless you are an electronics wizz, a software engineer and a risk taker you don't have much choice if you want this system. But sure it's only £85 (for a basic integrated thermostat alone), that will pay for itself, won't it? Well, yes.... and no.
Note: You "can" manually intervene to achieve this yourself without electronic control. As my own custom heating controller is off line since I upgraded my boiler and have not, yet, re-integrated it, I am doing it manually. My heating comes on at 4:30pm, I get home at 5:30, the boiler is set to 60*C shortly after the house is up to temp and comfortable. I set the heating down to 45*C and leave it running. Around an hour before I go to bed, the heating shuts off and I raise the temperature to 60*C again for the morning when it only runs for an hour to warm the house for the short period when I get up before I leave for work.
As I hinted to, I am a software engineer and I do electronics as a hobby and will accept this risks of doing this myself over the cost and privacy concerns of a proprietary system. No... I'm not selling it. I'll happily give you any of my software, documentation, design notes, circuit diagrams etc. for free though. The risks remain your own.
Thermostats and TRVs
This brings me to thermostats. In a lot of UK households you will find a single thermostat often placed in the downstairs hallway. You will find thermostatic radiator valves in every room (except the hallway).
This setup is a compromise, it's by no means ideal and neither that single thermostat, nor the TRVs will do a "proper" job, they just do the best they can while making it easy, convenient and most importantly easy to install and cheap. However without spending literally thousands of pounds on a fully smart integrated heating system it's about the best you can get. It's better to have them than to nothing.
So what are the compromises in that system? Well, to be blunt, it's quite simple.
1. Nobody cares what temperature it is in the downstairs hall, there is often only a very loose correlation between the hall temp and other rooms.
2. Nobody cares what temperature it is beside the radiator - there is never a good correlation between the actual room temp and the temp beside the radiator and more advanced electronics ones use complex machine learning to try and deduce the room temp.
... and this is exactly what this system aims to do.
I care what temperature it is on the sofa, I care what temperature it is in the bathroom when I take a shower, I care what temperature it is in the bedroom when I get up in the morning. I hate getting out of bed when the room is freezing, even if it's 20*C in the hallway or the temperature behind the bed where the radiator is in 20*C when the bedroom elsewhere is still 16*C.
So now we are advancing into what the future for efficient, environmentally friendly home heating should bring. I would propose...
1. Insulate your house - loft, walls, doors, windows, floors, while providing good ventilation.
2. Buy a modern heating system, either condensing natural gas (oil if you have to) or go for a heat pump system*. Properly balance your radiators, add radiator reflectors and maybe radiator fans for comfort in certain areas.
3. Place temperature probes in each room you care about the temperature in, place them near where you care what the temperature is, not beside the window or radiator.
4. Install electrically operated radiator valves (similar to underfloor manifold valves)
5. Install a smart demand based control unit that can monitor the temperatures, operate the radiator valves, alter the boiler flow temperature, switch the boiler on/off on timer or by demand.
6. Keep your house comfortable when you care about it being so, let it cool when you don't, but don't let it cool too far. If you let it drop below "dew point" condensation will form. Due point can be any where up to 10*C. So maybe something like, 19-20*C when home in the rooms we care about, 15*C overnight and 10*C as a minimum, even when on holidays.
In rooms you don't care about, fit a TRV as a compromise.
We need to encourage systems that can do this to be made affordable and force open standards upon HVAC equipment and software providers to make this more accessible for UK homes. You should be able to mix and match different brands in a single system to boost competition, flexibility and affordability. The data they collect and what they do with it, needs to be clearly outlined to the consumer and tightly regulated.
* Heat pump systems. Their rally cry is that they produce a kind of "over unity", in that they can provide upwards of 3 or 4 times the amount of heat compared to the electricity they use. The downside is that it takes 3 times as much fossil fuel to produce that electricity than it would yield if you burnt it in your boiler. For every kWh of electric, the power station burns 3 kWh of gas (give or take), so, like electric cars they are not anywhere near as green as they first appear. You can of course offset it with solar panels on the roof which is almost ideal, except of course it won't work on dark days or at night and produces much less in winter when you need more. The same can be said for your electric car. Solar storage systems are expensive, require maintenance, take up space and have environmental impacts and the most important factor everyone seems to forget, they are only practical if you are producing more power than you are consuming during the day.
The other downside that that heat pump systems tend to only produce low level heat, 40-45*C max, which is next to useless for warming a house up, but will provide a good effort at keeping it warm. Thus you might be best backing it up with an occasional use gas boiler or, if you must, electric heater.
On electric space heaters. There is only one use of these that is efficient. If you want to heat a single room to a higher temperature for a short time. It would be more efficient to use a small electric heater for a short time than to run the larger gas/oil boiler to heat a single room. A valid example might be an infrared heater in a bathroom. Although I'm not sure they will pass electrical safety codes these days, maybe they would.
Economy 7 was probably, money aside, the worst, least efficient, most environmentally damaging heating system ever introduced in the UK and probably several times worse than even coal fired heating. It was however great for electricity supplier profits.
Another thing I have seen that needs to be stopped.... people turning the heating on in summer just to dry clothes on the radiators. Don't do this, it's extremely inefficient! It so inefficient you would be better off using the tumble dryer!
One final comment.
Financially efficient != Environmentally friendly. Buying energy when it's cheap does absolutely zero for the environment, the fossil fuel still gets burnt. The only reasons electricity can be cheaper overnight is engineering reasons due to how supply/demand, electrical grid balancing happens and how power plants work. There are even companies who pump water up hill at night when electric is cheaper and use it to generate power on the way down when they can sell it for a higher price during the day. In real net terms this is a environmentally impacting waste. But people make money so it must be good, right? Wrong.
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Comments
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I agree.
Sigh, there's 10 minutes of my life I'll never get back :-(0 -
My position: I moved from oil fired vented to gas combi sealed system at the start of the month. My house lacks upgraded insulation and currently I only have a 7 day timer and the manual boiler temperature controls. I do have an automated, DIY, smart system in continued development which has led me to these postulations though analysis for the same, but that is not really the point of the post.
TBH, I CBA to read the entire post, but.... I'm in the process of improving my heating control system (a vintage Baxi back boiler, gravity system). Already have a Raspberry Pi monitoring the temperature in the hallway and switching the pump & boiler on/off depending on schedule and temperature. The software [1] is somewhat clunky and has certain shortcomings and I had to make a few alterations to get it to work with the sensors I have. That said, the graphs have been enlightening with respect to temperature changes along with just how long the boiler is running.
Next step is to add a few more sensors [2], add control for hot water, and generate even more data & graphs. Going to switch to a different software package [3] so that I have the option to add "smarts" for lighting at some point.
There may be value for us and others to compare notes and exchange ideas.- ttps://www.instructables.com/id/Raspberry-Pi-Home-Heating-Controller/
- https://www.aliexpress.com/item/32951321384.html
- https://www.home-assistant.io/
Some would probably say "Install Hive/Nest" and be done with it. I would rather not be tied to any web based app that requires a mobile phone or is reliant on an external service. The cost of a basic Hive/Nest control is far in excess of what I have had to pay for my system to date. I'm also not tied to either platform and free to choose sensors & controls from any number of sources.Any language construct that forces such insanity in this case should be abandoned without regrets. –
Erik Aronesty, 2014
Treasure the moments that you have. Savour them for as long as you can for they will never come back again.0 -
Buying energy when it's cheap does absolutely zero for the environment, the fossil fuel still gets burnt. The only reasons electricity can be cheaper overnight is engineering reasons due to how supply/demand, electrical grid balancing happens and how power plants work. There are even companies who pump water up hill at night when electric is cheaper and use it to generate power on the way down when they can sell it for a higher price during the day. In real net terms this is a environmentally impacting waste..
The point is, a power station's output can't just be turned up or down like adjusting the gas ring on a cooker. The output is, within tolerances and for all practical purposes, fixed. So if the generator is designed to provide enough power to meet the demands during the day, it'll be producing too much at night. You've got to either store that energy somehow, or waste it. Batteries are horribly inefficient at storing energy (though they're getting better, and indeed are the focus of a lot of research at the moment). But the "pumped storage" solution is just one way of storing the surplus energy - and when these storage plants were built, they were far more efficient than batteries by quite some margin.
The whole storage issue is becoming ever-more important with the growth of wind, solar, tidal etc. power. You've got to find some way of storing the energy when the sun is shining or the wind is blowing, ready to use when you can't generate the power. Like I say, there's a lot of research going into battery technology, and no doubt it'll become feasible in the near future. And there are plenty of other novel storage solutions being worked on, that may or may not become commercially viable. But until then, pumped-storage is as good as any, and doesn't require major investment as the plants are already there.0 -
Hi FreeBear,
Yes graphs alone are enlightening aren't they? I find I study them quite often and they have revealed things I would not have otherwise spotted.
This is my graph for today. Most things are in the legend, but the red shading is "presence", ie. I'm working from home (or chatting on MSE forums from home shhh).
The counterpart heating loop monitor:
On software mine is totally custom, firstly because I like the challenge, secondly it's actually easier than modifying existing software as I can tailor it exactly for what I need and only what I need without worrying about umpteen dozen different types of heating that I don't and won't have. Besides I don't exactly agree with how some systems choose to do things. eg. Electronic set-point radiator valves which are poorly thought out IMHO.
Home Assistant is brilliant. I would highly recommend it for many things, especially lights. However I would NOT at all recommend it for heating control and I think if you ask them on their forums you will receive much the same answer. Home Assistant is designed to integrate smart systems in one place so they can be automated, but something like heating control is a smart system in itself. I think the addige they use is "Don't make Home Assistant your thermostat, use home assistant to control you thermostat." So you should consider a heating controller that can be controlled and interfaced with from Home Assistant, but not actually using Home Assistant for it.
As to software design, if you PM me on here I'll send you a link to my development stuff on GitLab. But a few tips I will give you, if you want to do the design yourself.
1. Heating systems can be modelled as "demands" and "actions" or "commands" to satisfy demands. Decouple the two. Have one part determine what it thinks is needed and a separate part work out how to satisfy that. So neither need to really know how the other works.
2. Make everything fail safe. Default to OFF and SAFE. Make your demands and commands and states all expire. So if the system turns the heating on and then your Wifi fails or your Raspberry PI dies, the actual switch controlling the boiler will see the demand or command expire and will switch the heating off again.
3. Manual intervention can be done by the same mechanism of expiry times, but the automatics are not allowed to overrule a previous demand that hasn't expired, but manually generated ones (such as from an "Advance" button) can override the automatics.
PM me for more info.
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Ebe_Scrooge wrote: »The point is, a power station's output can't just be turned up or down like adjusting the gas ring on a cooker. The output is, within tolerances and for all practical purposes, fixed. So if the generator is designed to provide enough power to meet the demands during the day, it'll be producing too much at night. You've got to either store that energy somehow, or waste it.
This is certainly the case for nuclear plants as they tend to have a mostly fixed power output and changing the power level takes hours, not minutes.
However it is NOT true for gas turbines which can and are spun up and down in a matter of minutes. Increase the load the generator loads the turbine shaft which begins to slow it down, but as they all (ie, ALL turbines on the whole gid) are phase locked to the 50Hz mains grid and the turbine/generator shafts weight many tons, there is momentum enough to maintain the 50Hz speed while the gas turbine turns up by adding more fuel. When the current turbines/generators cannot supply the demand they have other unloaded turbines spinning already which they connect into the grid and direct steam to them. The same applied to coal fired as they don't really burn coal but virtually atomised almost liquid coal dust which is sprayed through a jet into the furnace and can be varied fairly rapidly.
A lot of pumped storage is used for "balancing" as sudden and large spikes or drop outs in demand happen in seconds, not minutes, so they use pumped storage with rapidly activating valves and ... possibly not the UK, batteries to help smooth these out giving the turbines they minutes to react.
When demand drops off they can disconnect turbines and turn down the gas quite quickly to prevent over spinning the connected ones. They just choose not.
The reasons they want to run them as hard as they can 24/7 are economical ones. The plants have a fixed life span. They cost money to build run and maintain. The more electricity they can make in that life time, the more they can sell, the more money they make, the more profit they make.
My comment was in relation to they much larger, mostly commercial pumped storage that takes advantage in the cycle of supply and demand to make money.The whole storage issue is becoming ever-more important with the growth of wind, solar, tidal etc. power. You've got to find some way of storing the energy when the sun is shining or the wind is blowing, ready to use when you can't generate the power. L
If you have a 37GW demand and only 20GW of wind/solar you aren't charging anything with wind/solar. In 10 to 20 years time when we have more than the current demand output being generated, then yes, storage becomes a viable option. Right now, solar and wind in the UK comes nowhere close to generating even the minimum base load, so there is no surplus energy to store.
(there might be small isolated overload scenarios where wind plants or solar plants have to be switched off as they would overload a certain area. This could use small localised storage to help, but the cost is staggering) Note, it's also a concern for grid operators around grid-tie solar as it can and does cause overloads at the local level as domestic solar systems will continue to raise the voltage to push their power onto the grid at some point the grid has to "pull the plug" on the whole area to prevent damaging things.0 -
Yes graphs alone are enlightening aren't they? I find I study them quite often and they have revealed things I would not have otherwise spotted.
Home Assistant is brilliant. I would highly recommend it for many things, especially lights. However I would NOT at all recommend it for heating control and I think if you ask them on their forums you will receive much the same answer.
I've only been collecting data for a couple of weeks now, but the graphs have given me some idea of how the temperature drops once the heating shuts down in an evening - Only lose around 2°C during the night at the moment. Will have to watch what happens when winter really bites.
Also collecting humidity data, and there a clear spikes when an evening meal is cooked or the washing up done - I get to see how long it takes for the lodgers to clean up after themselves (they are pretty good about it
).
Whilst I agree to a certain extent about HA, the core provides most of what I need. No point in reinventing the wheel. Once the bells & whistles that I don't need are removed, anything that I do need is fairly easy to integrate. Scheduling heating times needed a bit of head scratching, but easily solved by way of a Python script.
Sensors to date, are all hard wired (serial modbus), so no wifi or network to fail - I do agree with the sentiment of removing as many points of failure and defaulting to a safe mode when things do go wrong.
Will ping you later with a PM.Any language construct that forces such insanity in this case should be abandoned without regrets. –
Erik Aronesty, 2014
Treasure the moments that you have. Savour them for as long as you can for they will never come back again.0 -
I'm not reading that.Eat vegetables and fear no creditors, rather than eat duck and hide.0
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Will ping you later with a PM.
NM. Found your gitlab repository along with a long post on the HA forum. Without any docs, it is difficult to see how it would solve any of my problems. Sure, I could "read the code", but... HA has most of the features I need out of the box, and is easy enough to extend with a bit of Python coding.Any language construct that forces such insanity in this case should be abandoned without regrets. –
Erik Aronesty, 2014
Treasure the moments that you have. Savour them for as long as you can for they will never come back again.0 -
NM. Found your gitlab repository along with a long post on the HA forum. Without any docs, it is difficult to see how it would solve any of my problems. Sure, I could "read the code", but... HA has most of the features I need out of the box, and is easy enough to extend with a bit of Python coding.
All I can say is good luck with that. Anyway you know where the repo is if you want to take any ideas from it.0
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